1. Field of the Invention
The present invention relates to a finder mechanism and a drive mechanism, for use in a camera, which are projected and retracted in step with an imaging optical system.
2. Related Art Statement
A mechanism for driving a camera view finder is disclosed in Japanese Unexamined Patent Publication No. 8-313975. With a lens barrel interlocked with a view finder cam, the view finder drive mechanism projects and retracts a view finder optical system in step with the lens barrel that is projected, retracted and rotated. The view finder drive mechanism helps the make camera compact.
The camera with the above view finder drive mechanism includes an imaging lens barrel that is rotatable about an optical axis and movable between a projected position and a retracted position, a view finder having a lens movable along the optical axis, and a long gear and cam shaft for transferring the rotation of the lens barrel to the movable lens during the projection and retraction of the lens barrel. By means of the long gear and cam shaft, the rotary force of the lens barrel is transferred to the movable lens of the view finder to vary the magnification of the movable lens.
In the finder drive mechanism disclosed in Japanese Unexamined Patent Publication No. 8-313975, the lens barrel and the view finder cam are adjusted in phase with one another during assembly. This necessitates additional manufacturing steps, thereby increasing manufacturing costs. If an error occurs in an assembly process, disassembly and a reassembly of the camera will be required.
Disassembly and reassembly of the camera are also required when gears in a drive power transfer system in the view finder drive deviate as a result of gear tooth slippage.
The same problem is encountered not only in the view finder drive mechanism but also in a pop-up flash unit. As a unit driven together with the lens barrel, the pop-up flash unit is projected to its flashing position (pop-up position) from its retracted position in a camera body when the imaging lens is projected from its photograph-disable position (retracted position) to its photograph-enable position.